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bq24160 / D+/D- detection at switching power supply from IN to USB

S.Satoshi
Guru 21675 points

Hi All,

I understand that the D+/D- detection is performed after following behavior.

  • Both IN and USB are attached, and SUPPLY_SEL=1 (IN has precedence)
  • Switch SUPPLY_SEL from 1 to 0 during both  IN and USB are attached

Is my understanding correct?

Best Regards,

Sonoki / Japan Disty

  • 0
    TI__Guru*** 143870 points
    D+/D- is performed after V(USB) > VUVLO. The first step is to set USB ILIM to 100mA. The first step is D+, D- line connection detection as described in BC1.2. Primary detection begins 10ms after the connection detection complete. The primary detection complies with the method described in BC1.2. During primary detection, the D+, D- lines are tested to determine if the port is an SDP or CDP/DCP. If a CDP/DCP is detected the input current limit is increased to 1.5A, if an SDP is detected the current limit remains at 100mA, until changed via the I2C interface. These two steps require at least 90ms to complete but if they have not completed within 500ms, the D+, D- detection routine selects 100mA for the unknown input source.
  • 0 in reply to Jeff F
    Guru 21675 points

    Hi Jeff-san,

    Let me ask again for following two cases.

    Case #1

    1. AC adapter is attached to IN input first and start charging from IN
    2. CDP/DCP source is attached to USB input after that
    3. SUPPLY_SEL bit is changed from 0 to 1

    [Question #1]

    Is the D+/D- detection performed and USB input current limit set to 1.5A after SUPPLY_SEL bit is changed from 0 to 1? Or is it remain in 100mA(default) though CDP/DCP is attached?

     

    Case #2

    1. AC adapter is attached to IN input first and start charging from IN
    2. SUPPLY_SEL bit is changed from 0 to 1
    3. CDP/DCP source is attached to USB input after that

    [Question #2]

    Is the D+/D- detection performed and USB input current limit set to 1.5A after SUPPLY_SEL bit is changed from 0 to 1? Or is it remain in 100mA(default) though CDP/DCP is attached? This is the same question with #1

    Best Regards,

    Sonoki

  • 0 in reply to S.Satoshi
    TI__Guru*** 143870 points
    Changing supply precedence does not force D+/D-. Automation D+/D- detection only occurs if USB is plugged in while IN is not present. If the goal is to switch from IN to USB, you will need to force D+/D- detection after USB > UVLO, then switch supply precedence to USB.
  • 0 in reply to Jeff F
    Guru 21675 points

    Hi Jeff-san,

    I found D+/D–_EN bit in Control/Battery Voltage Register that can initiate D+/D- detection at any time. Then please let me know if the following understanding for D+/D–_EN bit is correct.

    • Set D+/D–_EN bit to 1 when both AC and USB (CDP/DCP) are present and SUPPLY_SEL is 0 (IN has precedence)
    • Then D+/D- detection run and USB input current limit is set to 1.5A
    • Remove AC and then charge source switch to USB with 1.5A USB input current limit

    Best Regards,

    Sonoki

  • 0 in reply to S.Satoshi
    TI__Guru*** 143870 points
    The steps you propose above are valid.